<style>
    table {
        margin: 0 auto;
        background-color: #fafafa;
    }
    td {
        padding: 6px 13px;
        border: 1px solid #ddd;
    }
    td h4 {
        text-align: center;
    }
    th {
        padding: 6px 13px;
        border: 1px solid #ddd;
        margin: 0;
    }
    table {
        border-spacing: 0;
        border-collapse: collapse;
    }
    code {
        margin: 0 .5em;
        border-radius: 4px;
        padding: 4px 8px;
        font-family: Consolas,Monaco,'Andale Mono','Ubuntu Mono',monospace;
        font-size: .8rem;
        background-color: #2d2d2d;
        color: #CC99CD;;
    }
</style>
<table>
    <thead>
        <tr>
            <th>名称</th>
            <th>规则</th>
            <th>含义</th>
            <th>允许示例</th>
            <th>拒绝示例</th>
            <th>备注</th>
        </tr>
    </thead>
    <tbody >
        <tr>
            <td><h4>required</h4></td><td><code>required</code></td><td>字段必须存在且不为空</td><td>-</td><td><code>null</code> <code>""</code> <code>[]</code></td><td>-</td>
        </tr>
        <tr>
            <td><h4>required_if</h4></td><td><code>required_if:field,value1,value2,...</code></td><td>如果<code>field</code>的值为<code>value1</code>或<code>value2</code>... 则本字段为 require</td><td>-</td><td><code>null</code> <code>""</code> <code>[]</code></td><td>-</td>
        </tr>
    </tbody>
</table>